FOAM LAKE BIRDINGNo. 27As I alluded to in the article on Chickadees, some of our permanent resident birds are more or less absent for the summer. It is not that they have migrated somewhere; rather, their nesting requirements dictated that they leave town for the breeding season. Woodpeckers, for example, need relatively large, dead or dying, trees in which to chisel out nests; and from which to extract worms and grubs to feed themselves and their young. Urban areas just do not have such trees available. Once the young have fledged, these “summer absentees” can be seen foraging on trees and visiting feeders in town.One of these summer absentees is the Hairy Woodpecker. It gets its name from its white back feathers which vaguely resemble hair – a feature not noticeable in the field.It is a striking black and white bird that has a clean cut appearance about it. The males and females are identical save for a small double red patch on the back of the male’s head. The double red patch lies horizontally across the back of the woodpecker’s head, and can only be seen when viewed directly from behind. When seen in profile, it appears as a single red square spot. One could compare them to human eyebrows. From the side they appear as only one; straight on there are two separated by bare skin above the nose. Occasionally, they merge into one “long” eyebrow with no separation above the nose. Sometimes, the Hairy’s spots also merge into one long stripe with no separation at the back of the head.As striking as they are, they are often overlooked because of their habit of clinging motionlessly to trunks of trees. The bird in this week’s photo sat motionless in that position for a good half hour! It certainly made for some leisurely photography. However, they usually give themselves away by calling out sharply, almost as if they wanted to attract attention to themselves.Like so many other birds, the Hairy Woodpecker has a “twin” as it were – the Downy Woodpecker. Except for some subtle size differences the two are almost identical. So, how does one tell them apart? The word, carefully, comes to mind. First, if the two are together, which often happens at feeders, size is diagnostic. The Hairy is robin-sized; the Downy is sparrow-sized (a large sparrow). Hairy Woodpeckers can vary considerably in size. A small Hairy will be only a little larger than a large Downey; a large Hairy can approach a Flicker in size. Second, when isolated, bill size is probably the most reliable and best distinguishing field mark. For a Hairy, the length of the bill from its base to its tip is about the same as the distance from the base of the bill to the back of the head. For a Downy, the length of the bill is about half the distance to the back of the head. With a little practice, it becomes easy to use this feature to tell them apart. This field mark always separates a Hairy from a Downy. Third, their calls, though similar, are different enough to serve as a good distinguishing characteristic also. The hairy makes a high pitched, sharp peek; the Downy makes a lower pitched and more subdued pickBoth woodpeckers will readily come to feeders if provided with suet or peanuts. The Hairy also eats fruit, but to get a fruit eater to a feeder is difficult. As of this writing, we have had a Hairy at our feeders, now we are waiting for its “twin”.